Hydration of olefines



ITP* 1369.13, 1938- i H. M. GUlNoT y 2,139,953'

HYDRATION oF OLEFINES Filed Feb. 26, 1956 HHH Hl i

ANDRA/5y Patented Dec. is, 193s I 2,139,915?,

UNITED STATES PATENT o'FFlcE 2,139,953 nYDnA'r'roN or oLEFiNEs Henri Mmm Guinot, more, Deux-sevres, France, assignor to Usines de Melle, Melle, France, a 'corporation of France Application February 26, 1936, Serial No. 65,916 In France March 22,1935

'z claims. (ci. 26o- 641) This invention relates to the hydration ofole- The extraction of the alcohol may be carried iines. out in a discontinuous manner, but is preferably It is well known to cause oleiines to act on carried out continuously even in the course of sulphuric acid with the object of being converted the operation of vsolution of the oleiine. The into corresponding alcohols. selected solvent is lemulsiiied with the hydrating \5 It has also been proposed to extract the alcosulphuric liquid and the mixture is then passed hols formed in this process by means of organic into a decanter where the solvent, which is solvents such as hydrocarbons, water-insoluble charged with alcohol, and the aqueous sulphuric aliphatic ethers or halogenated hydrocarbons. solution, which is returned to the mother solu- The object of the present invention is to rention, are separated. lb der this process of alcohol production easier and It is observed that the layer of solvent is always less expensive and to improve the yields of alslightly charged with sulphuric acid; it is treated cohol by employing as the organic solvent a with a small quantity of pure water which resolvent selected from the group consisting of 'the moves this acid (and a `small quantity of alcohol) phenols, .the cresols, their homologues, their from it, and the new dilute sulphuric solution l5 ethers and their phosphates. thus obtained is returned to the reaction vessel.

In a preferred way of carrying out the present As stated above, the quantity of water that is invention the concentration of the acid reaction used for effecting this washing shouldv be just solution is maintained by feeding back to it that which .corresponds to the quantity ,of water quantities of water equal to the amount of water that is necessary for the purpose of' nbtaining 20 absorbed in the hydration of the oleflnes, after the hydration of the oleflne treated. this water has been used for washing the acid The layer of solvent that has thus been defrom the solvent extraction mixture. It will be acidied is then freed, by simple steam distillaappreciated that the optimum acid concentration tion, from the alcohol with which it is charged. Will vary according to the nature of the oleiines The alcohol produces with the water an azeo- 25 treated. tropic mixture which always boils at a definitely Therefore the process according to the preslower temperature than the azeotropic mixture ent invention consists essentially in dissolving the formed by the water and the solvent employed. oleiine in an aqueous solution of sulphuric acid Consequently, this distillation does not involve sufliciently dilute to ensure that the alcohol exany difficulty, especially on account of the fact 30 iststherein in the free state, and in extracting that the alcohol is formed in advance in the the alcohol formed by means of a solvent which solvent. l is unacted upon by the acid solution, this acid The recovered solvent of the present process solution being re-used indenitely for dissolv- 1S, after being 000186. used again OI a fresh eX- ing fresh quantities of olenes. traction, and so on indefinitely. 35

However, if it is necessary that the sulphuric All these operations may be conducted at a acid solution to be usedfor dissolving the oleflne pressure which is different from the atmospheric should contain a fairly large quantity of water, pressure: Generally speaking, a raised pressure no general rule can be given concerning the is favorable, because'it enables a suiiieient speed 40 strength of the sulphuric acid to be used; this of solution of the oleiine to be obtained even with 40 concentration depends, above all, on the nature sulphuric acid solutions that are rich in water; ofthe olene treated; to as maller degree, it dei this leads, as has been seen, to purer reactions pends on other factors, such as the temperature, without the formation of undesirable products. the pressure, and the catalysts employed to carry A favorable action is likewise exerted by a modout the operation. erately raised temperature as well as by th'e em- 45 Be that as it may, -it is always advantageous ployment of the catalysts usually mentioned for to take an acid solution containing as much water this type of reaction, such as the/,oxides of copas possible, regard being had to the fact that one per, of silver, of lead, of bismuth, of gold, etc. is restricted inA this course by the very rapid The invention is applicable, not only to a pure diminution in the solubility of the oleflne in a oleiine but to an oleiine mixed with inert gases, 50 sulphuric acid solution of decreasing concentrasuch as saturated hydrocarbons, hydrogen and -tion. What is most important is that the sulnitrogen, and to mixtures of oleflnes lalone or phuric acid solution employed should not promixed with the' aforesaid inertvgases. duce polymers, or sulphurous acid or derivatives The following examples described with referof anylrind.l ence to the accompanying drawing will enable 55 the manner of carrying the invention into practice to be .well understood:

EXAMPLE l Manufacture of secondary butyl alcohol In a vessel I, having a useful capacity of 1000 litres and provided with a cooling system, there are placed 620 litres of an aqueous solution of vtion is about 50 cubic metres of butylene per hour; except for the starting period, a determination in iced water of the total acidity shows 99 percent. of the initial acidity to be existing in the free state.

When the content of free alcohol in the hydrating bath is of the order of 20 to 25 per cent. a certain volume of this acid liquid is taken and passed into a mixer 3 which is also fed by double the volume of solvent coming from a tank 5, this solvent being, for example, tricresyl phosphate.

The emulsified .mixture of the two liquids is passed into a decanter 4 where it separates into two layers, the upper layer consisting of the tricresyl phosphate containing in solution about 75 gms. per litre of secondary butyl alcohol together with a small quantity of water and sulphuric acid, and the lower layer consisting of the mother sulphuric solution still containing a certain proportion of unextracted butyl alcohol, in the present case about 100 gms. per litre. As the volume of the upper layer is nearly double that of the lower layer, gms. of alcohol per litre of sulphuric solution treated are thus extracted from the available 250 gms.

It is useless to endeavor to obtain a total extraction of the alcohol by the solvent. It is possible to do so by using a battery formed ofv a suiicient lnumber of elements, but this, as a general rule, constitutes a complication without a greatadvantage. It is simpler to increase the rate of circulation of the sulphuric liquid between the reaction tank I and the extraction system.

The acid solution thus separated in the decanter 4 is returned by the pipe 6 and the pump I into the reaction vessel I.` As to the slightly acid solvent, it is passed into a mixer 8 at the same time as a small quantity of water coming fro'ma tank 9. This quantity of Water corresponds to the'amount necessary-i. e., 36 litres per hour-for the hydration of the 50 cubic metres of butylene absorbed. Here, it might be o'f advantage for the work of de-acidiflcation to be eilected in a washing battery formed of sevtents. 'I'he water forms with the secondary butyl alcohol a mixture of fixed composition boiling at 87.5 C.; this mixture collects at the top of the column I2 whilst the excess 'of water and of tricresyl phosphate reunite with each other in the bottom part.

After being cooled'in vessel I3, the mixture of water' and tricresyl phosphate passes into a decanter I4; the aqueous top layer is thrown away and the recovered tricresyl phosphate is returned into the solvent tank by means of the pump I5.

The hydrated butyl alcohol obtained contains from 28 to 30 per cent. of water. It is dehy`y drated by known means and the pure anhydrous alcohol boiling at 99.5 C. is separated.

EXAMPLE 2 Manufacture of isopropyl alcohol The olefne treated is propylene. The work is carried out in an apparatus that is identical with that of Example 1. The acid employed is sulphuric acid of a strength of 75 per cent. strength and containing 0.5 per cent. of cuprous oxide. The solution' of the propylene is effected in the reaction vessel I, using a pressure of three atmospheres. The velocity lof absorption of the propylene in the hydrating liquid in the vessel I .is 20 cubic metres per hour reckoned at at.

mospheric pressure.

The extraction of the isopropyl alcohol is effected by washing the. acid liquid with three times its volume of butyl-cresci. When the bottom .layer owing from the decanter 4 still contains 100 gms. of alcohol, it is observed that the top layer of solvent' contains 50 gms. of alcohol. This, as in Example 1, renders necessary a slightly greater velocity oi circulation of the hydrating liquid between the vessel I and the extraction system; in any case, 150 gms. of isopropyl alcohol are extracted for every litre of acid liquid treated in the mix'er 3 and the decanter 4.

- In the same way as in Example 1, the reaction liquid remains at the same concentration indenitely, owing to the continuous additionvof Water coming from' ythe tank 9 and used for the de-acidication of the butyl-cresol.

The butyl-cresol flowing away at the base'of the column I2, mixed with an excess of water,

l is cooled in Vessel I3 and then. decanted in decanter I4. This time, the layer to be thrown away is the bottom layer. The top layer is returned to the solvent tank by the pump I5.

As for the isopropyl alcohol, it is obtained in the form of a binary azeotropic mixture at the top of the column I2; this mixture boils at 80.3 C. and consists of alcohol to the extent of 88 per cent. and of water as to the remaining 12 per cent. It does not decant. It is dehydrated, if necessary, by known methods.

EXAMPLE 3 l Manufacture of tertiary butyl alcohol The olene treated is isobutylene. The apparatus is identical with that of Example 1. The sulphuric acid used has a concentration of 58 per cent. and does not contain any catalyst. The reaction temperature is kept at about 50 C. Thework is carried out at atmospheric pressure.

The sulphuric solution, containing 250 gms. of the free alcohol per litre, is treated with one and a half times its Volume' of tricresol (an industrial product consisting of the three isomeric Acresols). After extraction, the solvent contains,

just as the sulphuric lacid`,\100 gms. per litre of the alcohol.

pure anhydrous alcohol which melts at 25 C.

and boils at 82.5 C. l

EXAMPLE 4.

Manufacture of amyl alcohol The olefne treated is trimethylethylene.

In this case, it is advantageous to send the olene into the reaction vessel l in the liquid state. The hydrating solution consists of sulphuric acid of 50 per cent. strength without any catalyst. The work is carried out under atmospheric pressure. The extracting agent is ethylphenol which is obtained by the action of ethyl alcohol on phenol in the presence of zinc chloride and consists of a mixture of isomers that is rich in the para derivative.

The solvent and the hydrating acid liquid are employed in equal volumes, the latter containing 20 per cent. of the alcohol in the free state.

The amyl alcohol is obtained at the top of the column I2 in'the form of a minimum boilingpoint mixture which boils at,8'l C. and contains about 30 per cent. of water. This mixture is heterogeneous; it is passed into the decanter I6 the amyl alcohol is obtained as the top layer; it is dehydrated by known means and separated in the pure state; its boiling point is 102 C. The aqueous bottom layer is continually brought back to the top of the distillation column I2 by a method of working which has now become classic.

These examples are not limitative and must not be regarded as restricting the scope of the invention.

What I claim is:

1. In a process for producing aliphatic alcohols by simultaneous absorption and hydration of the corresponding olefines in an acid absorption agent, the step of separating the alcohol.v

from said absorption agent by extractionwith an organic solvent selected fromy a group consisting of Vphenols, cresols, their homologues, their ethers and their phosphates.

2. In a process of producing aliphatic alcohols by the simultaneous absorption and hydration ofv the corresponding olenes in an acid absorptionagent the steps of ,separating the alcohol from said absorption agent by extraction with an organic solvent selected from a group consisting of phenols, cresols, their homologues. their ethers and' their phosphates, removing acid from said solvent by washing with water and returning said washing water to the vessel containing said absorption agent.

3. In a process of producing aliphatic alcohols by the simultaneous absorption and hydration of the corresponding olenes in an acid absorption agent, the steps of separating the alcohol from said absorption agent by extraction with an organic solvent selected from a group consisting of phenols, cresols, their homologues, their ethers and their phosphates, removing acid from said solvent by washing with water and returning the said washing Water to the vessel containing said absorption agent, the quantity of water being used for this washing corresponding exactly to the water absorbed by the hydration of the olene.

4. In a process of producing aliphatic alcohols by simultaneous absorption and hydration of the corresponding olenes in an acid absorption agent, the steps of separating the alcohol from said absorption agent by extraction with an organic solvent selected from a group consisting of phenols, cresols, -their homologues, their ethers and their phosphates, and separating the alcohol and the solvent from each other by azeotropic distillation with steam.

5. A process of producing aliphatic alcohols which comprises absorbing the corresponding olenes in an aqueous 4solution of an acid absorption agent, extracting the alcohols formedwith an organic solvent selected from the group consisting of phenols, cresols, their homologues, their ethers and their phosphates, removing acid from said solvent and separating -the alcohol from said solvent by azeotropic distillation by means of steam.

6. A process of producing aliphatic alcohols which comprises absorbing corresponding olenes in an aqueous solution of an acid absorption agent, extracting the alcohols formed with an organic solvent `selected from the group consisting of phenolsf cresols, their homologues, their ethers and their phosphates, removing acid from said solvent by washing with an amount of water equal to the amount of water absorbed in the hydration of said oleflnes, separating said washing-water from the solution of the said sollogues, their ethers and their phosphates, allowing said agitated mixture to settle, returning the acid aqueous solution produced by said settling back to said main reaction chamber, transferring the solution of acidifled solvent and alcohol to an agitator, agitating said solution with a quantity of water equal to the amount of water absorbed by the hydration of the olene in said main reaction vessel, allowing said agitated solution to settle, returning to the main reaction -vessel the solution of acid in the added water,

transferring the de-acidiiied solvent and alcohol to a still, and separating alcohol from said solvent by azeotropic distillation by means of steam.

- l HENRI MARTIN GUINOT. 

